Aircraft tail chassis



April 1932- I K. HENRlCHSEN 1,855,020

AIRCRAFT TAIL CHASSIS Filed Oct. 29, 1929 INVENTOR Mar flmw/cHsE/v BY II Q ATTORNEY V 5 matically and resiliently maintaining such bodiment ofm invention, with part of one Patented Apr. 19, 1932 UNITED STATESPATENT OFFICE I KN'OT HENBIGHSEN, OF GARDEN CITY, NEW YORK, ASSIGNOR TOGURTISS AEROPLANE 8a MOTOR COMPANY, INC., A CORPORATION OF NEW YORKAIRCRAFT TAIL CHASSIS Application filed October 29, 1929. Serial No.403,178.

This invention relates generally to aircraft clearly, one embodimentthereof is shown in and especially to an improved tail chassis theaccompanying drawings, in which: suitable. for use with aircraft. It ismore Fig. 1 is a side elevation of the rear porspecifically concernedwith means for autotion of an airplane equipped with one ema tailchassis at a normal central position of the springs roken away to showits con- 56 and for returning it to such position after it struction.

has been displaced therefrom. Fig. 2is a horizontal section of thedevice Prior to my invention there have been deshown in Fig. 1 taken onthe line 22 therevices provided for the same purpose, but of; and

these prior devices usually consisted of a pair Fig. is a horizontalsection of the device of springs connected to spaced points on shown inFig. 1 taken on the line 3-3 theresome part of the tail chassis and alsofastened fto fixed points on the airplane fuselage in In general, thedevice used in illustration [5 such a way that the two springs pullagainst of my invention comprises a tail wheel each other to maintainthe tail chassis in subm nted upon shock absorbing struts. Thestantially central position. Such devices are slilllts are in urnmounted upon a substanbj ct t v l di d t If one tially vertical axisshaft for rotation in a spring become weak th n th th th substantiallyhorizontal plane in order that n tail chassis is maintained, not in itscentral h Whe l m y ll h i p in its p h position, but to on id th f t dth acrossthe landing field and in its turns as it strong r ing, D t th td use d= 1S taxiing. The shaft has fixedly secured variations in thetension imposed upon the thereto P 0f collars i g h having springs, itis apparent that, even if the springs a shoulder formed therewith.Between :5 are of equal tension when originally ad usted, these ringsthere is inserted for'flee i n 0 an aerial vehicle which means will havemore descl one of them is 'apt later to become weakened 011 P Shaft 8 POf s p memb rs each more than th oth having a shoulder cooperating withthe O f th bj t f my i ti i t shoulder of its associated ring and eachprovide means for centering the tail chassis of havln 3 P m g hook p pto be ibed. Between the lugs around the 88 equal and uniform a ti n th di shaft there is also inserted a helical spring vlously used. in suchfashion that its ends bear upon A further object is the decrease ofweight shoulders 011 the two p members to urge in th t il h i 45 i ftthe hooks on both stop members toward a 5 Afurther object is thedecreaseinthe num- P which is fixed t the airplane 513111;?

ber of parts of the chassis of aircraft. i substmtiauy Parallel to thefirst A further object .lch an arrangement of honed fif l 11.13011 f iOf mi the parts of the tai assis of an aerial vehii' either dlrectmn? mespnng 338x561; cle as to enable ti use of a more eflicient to tum itback to normal In the drawiii s I have shown an arran esprmg forcenterin Lit llihaSS1S,at01SlO11 g r a I s spmg bang e ea srmss- 21352;; iiiilifng inh 22253; lihiif" iii- A fmither Oblect' i i fi j m ofer'ring specifically thereto, 51 represents a 10W P E for use the landmglongitudinal element of the fuselage of an and taming Shocks 9? aircraftairplane. Rig-idly secured to the element 11 Further oblects wig be PP310m 3 is a substantially vertical tail post 12. Supreading of the suboined specification and ported at the opposite ends of the post 12 areclaims and from a consideration of the draw journals 13 and 14 which maybe, if desired,

mgs, formed as a part of the fuselage structure. v D In order to explainthe invention more Journaled in the bearings substantially pars 10oallel to the tail post 12 is a shaft 15 which serves as an axis for thestruts of the tail chassis. The upper strut 16 may be pivotally fastenedas at 18 to a fitting 17 rigidly secured to the upper end of the shaft15 and a lower strut 20 may be likewise pivotally mounted as at 18 to afitting 19 secured to the lower end of the shaft 15. The struts 16 and20 may be each provided at their lower ends with yokes which yokes maybe pivotally joined as at the pivot 18 and may carry upon the pivot 18",the landing wheel 21. The strut 16 may comprise telescoping memhersforming an oleo shock absorber and may have secured to the telescopingmembers,

flanges 22 and 22*, respectively, between which is inserted a helicalcompression spring 23. This spring, as shown at 24, may be of the hollowtype in order to increase its strength-weight ratio.

I have also provided means for returning the above mentioned parts totheir normal central position. Fastened to the shaft 15 intermediate itsends are collars or rings 27 and 28. The collar 27 has a downwardlyprojecting shoulder 29. A stop member 30 is mounted for free rotationupon the shaft 15 beneath the collar 27. The stop member 30 hascooperating shoulders 32 and 33 designed to cooperate with the shoulder29 and a shoulder 31 designed to cooperate with a spring 35. It isnormally resiliently held with its nose or hook 34 against the tail post12 by the spring 35, which spring 35 is normally under a slight stress.The spring 35 may be hollow, if desired, and is inserted around theshaft 15 beneath the stop member 30. A similar lower stop member 36 isalso loosely rotatable about the shaft 15 and is positioned beneath thespring 35 but above the collar 28. The collar 28 has a stop lug 37 whichprojects upwardly to cooperate with shoulders 38 and 39 formed on thestop member 36. The spring 35 bears against a shoulder 40 on the stopmember 36 and tends to maintain the nose or hook 41 of the stop member36 against the tail post 12.

In the operation of this embodiment of my improved centering device, thetail chassis is normally held in such a position that the wheel 21 formsa substantially longitudinal continuation of the fuselage of theairplane. However, due, to turning of the airplane or irregularities inthe ground, or both, the wheel may be resiliently moved to one sideorthe other, rotating with the shaft 15 in the journals 13 and 14. Uponmovement of the wheel 21 to the left (looking forward) it is evidentthat the stop member 36 will be standing lug 37 with the shaft 15, andby reason of the contact of the lug 37 with the shoulder 39 of the stopmember 36. This moves the lower end of the spring 35 clockwise lookingdown, and as the upper end of the spring 35 abuts against the shoulder31 of the stop member 30 and the nose 34 of the stop 30 is held againstmovement by the tail post 12, the spring 35 is placed under greaterstress and there is a tendency as soon as the force moving the wheel 21is removed, to return the wheel to its original position. In the sameway, if the wheel is turned to the right, the stop 30 moves away fromthe post 12 and the stop 36 being held by the tail post. 12, the spring35 is similarly placed under tension and when released, tends to movethe wheel back toward its normal position.

It is to be understood that the above described embodiment of theinvention is for the purpose of illustrationonly and various changes maybe made therein without departing from the spirit and scope of the in--vention.

I claim as my invention:

1. In a tail chassis for airplanes, means for absorbing landing shocks,pivotally mounted upon a part of the airplane, and means for yieldinglyurging the absorbing means to a normal central position, said last namedmeans comprising a single spring, a shaft upon which the absorbing meansis pivoted, and a pair of floating lugs rotatively mounted upon saidshaft.

2. In a tail chassis for airplanes, means for absorbing landing shocks,pivotally mounted upon a part of the airplane, and means for yieldinglyurging the absorbing means to a normal central position, said last namedmeans comprising a single spring, a shaft about the axis of which theabsorbing means is pivoted, a pair of floating lugs rotatively mountedupon said shaft, and a pair of sta tionary lugs fixed to said shaft:

3. In a tail chassis for airplanes, means for absorbing landing shocks,pivotally mounted upon a part of the airplane, and means for yieldinglyurging the absorbing means to a normal central position, said last namedmeans comprising a shaft about the axis of which the absorbing means ispivoted, a pair of floating lugs rotatively mounted upon said shaft, apair of stationary lugs fixed to said shaft, and a helical springsurrounding said shaft and having its opposite ends bearing upon therotatable ugs.

4. In a tail chassis for an airplane; a substantially upright memberfirmly secured to the framework of the airplane; a pair of spacedbearings secured to said upright member; a shaft carried in saidbearings in sub stantially parallel relationship with the uprightmember; a strut secured to the lower end of said shaft; a resilientstrut secured to the upper end of said shaft; a""tail wheel supported bythe lower ends of said struts; a pair of lugs secured to said shaft;each of said lugs being provided with a shoulder; a pair lbs of floatinglugs mounted on said shaft for substantially free rotation thereon andeach having a pair of shoulders, one of each pair being adaptedtocooperate with the shoulder of one of the fixed lugs; and a spiralspring having one end bearing against a shoulder formed on one of thefloating lugs and the other end bearing against a shoulder formed on theother floating lug; each of the floating O lugs having a projectionadapted at times to contact with said upright member.

5. In a tail chassis for airplanes, means for 'absorbing landing shockspivotally mounted upon a part of the airplane, and means for yieldinglyurging the absorbing means to a normal central position, said last namedmeans comprising a shaft upon which the absorbing means is pivoted, anda single torsion spring encircling said shaft. In testimony whereof Ihereunto aflix my signature.

KNUT HENRICHSEN.

